1. Field of the Invention
The present invention relates to an ink composition and to a recording method and recorded matter in which this ink composition is used, and more particularly relates to an ink composition with excellent gas resistance, fixability, and bronzing resistance.
2. Description of the Related Art
One type of ink used in ink jet printers is pigment-based inks in which a pigment is used as a colorant for the purpose of enhancing resistance to light and water. However, these pigment-based inks do not have adequate fixability with respect to paper or OHP, and it has also been indicated that there is room for improvement in terms of the water resistance of the printed matter, printing characteristics, ink bleeding, and so forth.
In view of this, and in an effort to solve the above problems, a water-based ink has been disclosed in Japanese Patent Application Laid-open No. H 11-217525, for example, in which ink bleeding, water resistance, and fixability are improved by sulfonating a diene-based (co)polymer whose essential component is a diene monomer, and emulsifying and dispersing this along with water in the presence of a dye or pigment (Patent Document 1).
However, if a recording medium having an ink accepting layer is used as special ink jet paper, then problems encountered with conventional ink compositions in solid printing include a phenomenon in which reflectivity varies with the printing duty, a phenomenon in which cyan solid printing takes on a reddish look (hereinafter referred to as “bronzing”), and inadequate fixability of the ink composition.
Also, printed matter produced using an ink composition is sometimes left outdoors, where it is exposed not only to sunlight but also to other types of light and to the atmosphere (which includes ozone, nitrogen oxides, sulfur oxides, and so forth). Accordingly, it is preferable for an ink composition to have excellent resistance to light and gases.
In view of this, the present invention was conceived in order to solve the problems encountered with the above-mentioned prior art, and it is an object thereof to provide an ink composition with excellent bronzing resistance, gas resistance, and fixability.
It is a further object of the present invention to provide a recording method and printed matter in which the above-mentioned ink composition is used.